The invention relates to a device and method for unloading a container. For instance, while items of mail are being conveyed, the task arises of removing an article from an open-topped container. The article is, for example, a stack of mail items. The items are, say, standard-sized or large letters or possibly catalogs. The items of mail are prior to being removed located in an open-topped container into which they are placed after being brought in, for example. If removal is in an upward direction then the force of the items due to weight would need to be compensated by means of, for example, lateral limiting elements. It is, though, desired for the items of mail not to be damaged while being removed from the container, which is why the limiting elements must not exert too great a holding pressure.
U.S. Pat. No. 4,744,715 describes a device for unloading a container having a removal opening for removing an article. The article is in that case a “wafer”. Prior to unloading, the article is located in the container of a type such that the article can be removed through the vertical removal opening. The container rests on a supporting surface which, being mounted on a driven hollow shaft, is mounted rotatably. The article is prior to being removed held in the container by two retaining elements. The retaining elements are mounted rotatably on a shaft ducted into the supporting surface's hollow shaft. The container is tilted through 90 degrees so that the removal opening points downwards. The retaining elements prevent the article from dropping out of the container. A further supporting element is moved into a position beneath the article. The retaining elements are both removed so that the article rests on the supporting element. The container is swiveled into its initial position.
WO 98/23393 A1 describes how a receptacle filled with postal items is emptied. The receptacle is prior to unloading positioned in such a way that the removal opening points upwards and postal items rest horizontally on two inclined faces in the receptacle. A pickup and transfer head is positioned above the receptacle. The head has an L-shaped component one of whose limbs is applied against the receptacle wall. Secured to the other limb are pressure pads that compress the stack. The head raises the receptacle and turns it. The receptacle can then be lifted off and the stack further processed.
DE 19905955 C1 describes a method and device for unloading an open-topped container containing postal items. Retainer supports between which the stack of postal items is clamped are moved into the open-topped container. The container is turned through more than 90 degrees, producing a gap between the stack and the then upward pointing container bottom. A moving stop wall prevents the postal items from dropping out of the container. A base plate is pushed into the gap, and the container is turned back. The stack, resting on the base plate, can be removed from the container.
EP 0716891 A1 discloses a device for lifting a stack of flat articles into a container. The stack is therein aligned then compressed by two limiting elements and lifted. A container is moved into a position beneath the lifted stack and the stack then lowered into the container. Those steps of the method can be performed also in reverse order.
EP 1437183 B1 describes a device having a support means for supporting the filled container. The support means is mounted rotatably. The container can be turned and the items of mail removed from the turned container.